Prostate cancer is the most frequent cancer in males in the United States and the cause of nearly 31,000 deaths per year. When diagnosed early, cancer can be effectively treated by surgery or radiation. Postsurgical residual disease requires radiation and/or hormonal therapy, which may prevent tumor progression and metastasis. At present, there is no curative treatment for hormone refractory, metastatic prostate cancer. Immunotherapy is a targeted therapy that in principle provides for the treatment of such cancers.
Targeted T cell therapies utilizing genetically modified autologous T cells are beginning to show evidence of therapeutic efficacy in melanoma and indolent B cell malignancies. Current T cell engineering strategies retarget patient T cells to tumor antigens through a transduced T cell receptor (TCR) or a chimeric antigen receptor (CAR). The newfound ability to induce potent immune responses, however, commands the need to confine immune attacks to the tumor and avoid reactions against normal tissues that may express the targeted antigen. Alas, the limited availability of truly tumor-restricted antigens often precludes achieving highly specific targeting is the limited availability of truly tumor-restricted antigens. Accordingly, new methods of treating neoplasia are urgently required.